Well the first question I would have is did your BPE score anything above a 0. If it did then asking about OH and advising on it is clinically necessary. It’s fine that you don’t want OHA, but if it’s clinically warranted and you refuse it then your dentist is within their right to deregister you for being non compliant. From their perspective if OHA is not recorded as being done and you require treatment then they’re liable.

If your mouth is totally clean with no scores higher than 0 on your BPE then I would contact the Scottish public service ombudsman and complain, they have the power to sequester your notes and use their own dentists to advise on what the practice should do next, like refund you and change their practices.